1. Field of the Invention.
This invention relates to can straightening devices, and particularly to a can straightening device for straightening full cans of food product after they have been bent.
2. Description of the Prior Art
A preliminary patentability and novelty search in connection with this invention has revealed the existence of U.S. Pat. Nos. 2,736,359; 2,855,972; 3,336,786 and 437,702.
Referring to each of the patents in the order of their issuance, U.S. Pat. No. 437,702 is a very early patent and relates to a structure for stretching helical springs beyond their elastic limit to form a straight bar or rod. Obviously, the device disclosed by this patent has no relevance with regard to the straightening of a bent can full of food product.
U.S. Pat. No. 2,736,359 relates to a device for stretching automobile door panels to restore the door panels to their initial configuration. Again, the structure disclosed by this patent is totally different from the structure disclosed and claimed herein and is used for a totally different purpose.
U.S. Pat. No. 2,855,972 performs the same function as the previous patent, but utilizes a still different structure. In this device, hydraulic fluid is used to expand a device to impose a straightening force on the skin of a door panel being straightened. It is apparent that there is no mechanical or functional correspondence between the teaching of this patent and the invention disclosed and claimed herein.
U.S. Pat. No. 3,336,786 relates to a tool for straightening the spindle of a bicycle fork in relation to the fork portion. This tool permits this to be accomplished without removing the front wheel. Structurally, this device is very different from the invention disclosed and claimed herein, and functions by a different mode to accomplish a different purpose. Accordingly, there is nothing in this patent to suggest the structure disclosed and claimed herein.
In the food industry, particularly in the canning industry, there are two types of containers that are utilized for containing the food products that are canned. One of these is a metal can into which food product is deposited to a predetermined level, which is then caused to pass through a series of retorts where the food product and can containing the food product is subjected to high temperatures to cook the food product, the can subsequently passing into a sealing mechanism for sealing the can after the food product has been cooked. The cans then proceed to the end of a conveyor line where the cans are off-loaded onto pallets, and the pallets then transferred to a warehouse where the cans are stored for subsequent labeling. The contents of the cans are indicated on the lid of the can by indicia which can be numbers, letters or alpha-numeric indicia constituting a code that indicates the contents of the can.
Subsequently, upon receipt of orders to ship a particular food product contained in a can, the cans are selected from the warehouse, pass through a labeling machine that applies a proper label to the can so that prospective customers may see at a glance what the contents of the can are, and the canned food product is then shipped to food distributors or food brokers or ultimate consumers.
The metal containers of food product are sometimes bent to the point that the labels cannot be applied to the cans. The cans are usually not ruptured so as to spoil the contents of the can, but it is impractical to ship the cans if an appropriate label cannot be applied. Cans of food product may be bent in many different ways. Employees may inadvertently drop a pallet of cans, in which case, the cans strike against each other and against other objects, or fall with high impact on a cement floor, or the bending of cans may occur because of catastrophic events such as earthquakes. For instance, in the Oct. 17, 1989 earthquake that occurred in California, many hundreds of thousands of cans of food product of many different types were bent not only in stores where consumers had access to the cans, but also in warehouses before such cans were labeled. Where the bending of the cans occurs after the labels have been applied, it is not too much of an economic burden on the owner of the food product because they may still be sold, albeit generally at a reduced price. However, when the bending of the cans occurs prior to labeling, a different problem is presented because the cans cannot now pass through labeling machines, and even if they do pass labeling stations, the cans can frequently be bent so badly that the labels will not adhere to the non-cylindrical bent surfaces of the cans. Accordingly, it is one of the important objects of the present invention to provide a can straightening apparatus on which sealed full cans of food product may be acted upon in a manner to straighten the cans sufficiently to enable the placement of a label thereon.
Experience has taught that when cans fall or roll about indiscriminately striking other cans and other objects, or when they are tumbled in mass from pallets stacked to great heights of fourteen or fifteen feet, the type of bending that occurs is indiscriminate, each can being bent differently than other cans and some of the cans being bent in several locations about their cylindrical surfaces by the creation of irregular indentations in the cylindrical sides of the can. Accordingly, a still further object of the invention is the provision of an apparatus that will accept such a can having multiple indiscriminate bends in the sidwalls thereof and which by appropriate manipulation will effectively straighten the can sides by eliminating or significantly reducing the indentations to thus permit the application of a label on the can.
When food product packed in cans pass through the high temperature retorts to cook the food product, the food product is heated to a high temperature and air is driven from the inside of the can. Subsequently, the sealing process proceeds while the food product and the can are still very hot. Accordingly, when the sealing has been completed, and the can is permitted to cool, there is a tendency for a slight vacuum to be formed in the sealed can by virtue of the contraction of the hot food product within the can as it cools. When a can containing a slight vacuum such as just described is bent, particularly when it is bent in many different indiscriminate locations about its cylindrical surface, it is frequently necessary to straighten the cylindrical sides of the can by the application of tension on the opposite ends of the can at several locations around its periphery. Accordingly, a further object of this invention is the provision of a can straightening apparatus that may be manipulated to apply such tension on the sides of the can repeatedly in different locations around its circumference.
The invention possesses other objects and features of advantage, some of which, with the foregoing, will be apparent from the following description and the drawings. It is to be understood however that the invention is not limited to the embodiment illustrated and described since it may be embodied in various forms within the scope of the appended claims.